Firstly do you know what the requested decel rates are?
RTO - max pressure. No specified rate.
Landing
low,Med,Hi
No published decel rate.
For anyone who likes their trivia the rates are 4,8 and 13 ft/s^2 but the only place you will find those numbers are in the manufacturers system description reports. They don't appear in any of the operational documents as you don't have a decel meter with which to measure normally.
I say normally because if you have HGS with HUD3A certification then you get low Med Hi markers on the combiner display and the accel pointer will then show if you are achieving the selected rate.
The Autobrake uses the current decel rate compared with the requested rate to calculate the brake command in the landing mode. The aircraft not achieving the requested rate will simply cause the AB to request more pressure.
The AB will declare "FAIL" if it looses communication or has an internal fault. This will cause the selector to go to the OFF position and the EICAS " AUTOBRAKE FAIL" message.
Last edited by FE Hoppy; 27th November 2009 at 13:49.